Telephone system



NOV. 10, 1931. c, SPE ET AL 1,831,398

TELEPHONE SYSTEM Filed Jan. 27, 1931 2 Sheets-Sheet l Nov. 10, 1931- c. G. SPENCER ET AL TELEPHONE SYSTEM Filed Jan. 27, 1931 2 Sheets-Sheet 2 R M M A M 5 A J C m m y N 5 w w wst vww Q .l |I

MON QQN ATTORNEY Patented Nov. 10, 1931 UNITED STATES CHARLES G. SPENCER, OF EAST ORANGE, JERSEYQAND JOHN A. HALL, OF BAYSIDE,

NEW YORK, ASSIGNORS TO BELL TELEPHONE LABORATORIES, INCORPORATED, OF

NEW YORK, N. Y., A CORPORATION OF NEW YORK 'rnnnrnonn SYST M;

Application filed January 27, 1931. Serial No. 511,460.

This invention relates to telephone systems and particularly to an arrangement for connecting operators telephone sets to operators link circuits. i

The object of the invention is to provide means whereby a subscriber who is a party to an established connection may recall the operator and actually cause a connection between her telephone set and the link circuit through which his connection is to be established instantly if she is idle'or if she is busy then as soon as she becomes idle.

In accordance with one feature of this-invention a means is provided responsive to the idle condition of the operators set for connecting such set to a link circuit on. .which'a recall condition has been established.

In accordance with another feature ofthis invention a means is provided for displaying a signal beforean operator which is-distinctive and indicative of the fact that her tele' phone set has been automaticlly connected to link circuit on which a recall condition has been established: 1 I v The drawings comprisetwo sheets of circuit diagrams which whenplaced with Fig. 1 above Fig. 2 illustrate the present invention. Fig. 1 shows a number of circuits that are common to a plurality of cord circuits, one of which is shown in full in Fig. 2 and a second of which is indicatedMin -that figure. The common circuits of Fig. 1 include the operators circuit shown in the upper left hand enclosure, the common ringing key circuit shown in the upper right hand enclosure, 1 a low rate interrupter circuit and a high .rate interrupter circuit shown in the small enclosures below the operators circuit, and the ringing generators shown in the enclosurebeneath the common ringing key circuit.

' 1 When the position is occupied by an operator, the operators telephone circuit plug is in the circuit jack and relay 100 is operated in series with the operators transmitter 101 and the primary 102 of the induction coil. The receiver 103 is bridged across the secondary coil 104 and the talking leads 105 and 106 are connected to the outer terminals of secondary coils 104 and 107.

We will now assume that a call is being "111 and 112 in series and thence in one direction through resistance 113 to battery and in theother direction through resistance 114, the front contact and armature-of relay 100 PATENT oFFIC-a toground. Both relays 111'and 112 are polar- V ized and each responds to current in-a differentdireotion. If the plug 202 is the first to be placed in jack 203 or another jack multipled thereto, a simple groundwill be found on the sleeve and relay 111 will operate. If jack 203 has already been rendered busy by the insertion of another plug in a multiple jack, then battery potential will be found on the sleeve of jack 203 and relay 112 willrespond. In the case of a busy line, when relay 112 responds, acircuit is established for relay 115 which connects through its front contacts a busy tone to the operatorsfset so that she will know that she has plugged into a busy line.

We will assume in this case that relay 111 operates. Thereupon, a circuit is established for relay 110 and this relay now looks to conductor 108 through the front contacts of-its inner right hand armature. vAt the same time, relay 110 removes battery from conductor 116 for purposes which will beexplained hereinafter. Upon the operation of relay 110 and the substitution of a connection to conductor 108 which extends in one direction through the resistance 117 to battery and in the other direction through the. right hand winding of relay 110 to battery, relay 204 responds.. Thereupon a circuit; is established through the winding ofrelay 204, the contacts of relay 205, the alternate contacts of the upper outer armature of relay 204, conductor 118, winding of relay 119 to battery. Through the action of relay 20 1, the ground connection on conductor 108 is removed and relay 110 is released. Although relay 110 now closes the battery connection to -conductor 1116, relay 119 opens it at its inner ri-ghthand armature and back contact. At the same time relay 119 through its outer right hand armature places ground on conductor 120 for purposes which wlll appear hereinafter.

Relay 204: in operating now connects ground and battery through its innerarmatures to the tip and ring conductors of plug 202 and thus supplies talking battery to the substation 200. Supervisory relay 206 is serially included in the ring'conducto-r and thus becomes operated.

Further, upon :the operation of :relay 1204,

a circuit is established from battery, the low- :er armature and second front contact thereof,

Winding of relay 201, normal contacts of the inner left hand armature :of relay 3208 to ground. Belay 207 operates:andiconnectsthe operators headset to the cord. Such a connection 'may be traced from conductor 106 through the upperarmature' and back contact of relay 115, conductor 121, the outermost upper armature and front contact ef ael'ay 207, conductor 209 outer upper armature and back contact of relay .21 0, upper left hand winding of induction coil 1211 to ground :and thence from battery through the lower an hand winding of induction :coil 211, calling supervisory relay 212, front contact and outermost lower armature of relay-2057., condnctor 122, condenser =123,bacl( contactxazndllower armature of relay 115 to conductor 105.

The operator now learns tfrom th'e calling opens the original energizing circuit of relay 119 and closes a direct battery connection through its front contact, resistance 121 5, winding of relay 52041 to ground on the s'leeye Upon the depression of key 124:, relay 125 is operated. This relay through fits right hand' arm'ature places ground from the contacts of key' 12' throughits secondary front contact to cause the operation "of "relay 126 and connects ground-through its right hand armature and frontco'ntactand the outer left hand armature of relay "126 to the winding of relay 127. Re-lay 127 places ground on conductor 128. Relay 125 through its left hand armature p laces ground on conductor 129.

' When relay 205 operates a circuit is :es-

tablished from battery, winding of relay 119, conductor 118, front contact and inner lower armature of relay 205, back contact and right hand armature of relay 208, conductor 130, winding of relay 131 "to ground; .Rel-ay 131 through i'tsin-i-ier'right hand armature places .a ground on the right hand armature of relay 125 to maintain this relay and relay 126 locked afterthe key12 1hasbeen released. Through its innerleft hand armature,relay 131 placesa' ground on the front'conta'ct of the inner left hand armature of relay 126 whereby peg count meter 132 is operated.

WVith groundplaced on conductors 128 and 129, the following action takes place. Ground :on conductor 129 may be traced through the innermost upper armature and ront :contact of relayt207, Winding of relay 216, conductor 217, front contact and inner thus relay 2 16 locks through itsown left hand armature and front :contact.

A' circuit 'may also 'be traced from battery through the right hand armature and front contact of relay 126, "the front contact and :outer left hand armature of relay 4131, conductor 133, the innermost lower armature and "front contact of relay 1207 inner lower armature and-back contact of relay 1218,

Winding :ofrelay 218, the back contact and armature of relay 219 to ground. Relay'218 operates and looks through the alternate contacts of its vinner lower armature to the battery on conductor 217.

Ground n1 ay now be traced from conductor 128 through the middle lower-armature :a'nd 'front contact of relay 207, Winding of relay 208 to battery on conductor 217. Relay 208 operates and looks through its inner left hand armature and front contact to ground. At this time the series connection from "hattery connected ito one terminal of relay 119 to ground connected to one terminal of relay 131is opened at the back contact and right hand am'nature of relay 208 and then both the operators setrand the common ringing key set are released and retired.

Ringing "current is now connected to the called subscrihers line from conductor 134; throughthe f-rontcontact and left hand armaturezo f relay 2:16, winding of relay 21-9, the back contact and inner upper armature of relay 21.0, the front contact and outer upper armature of relay 218, the norma'lcontacts of key 220, tip of plug 213, thence-out over the su'bscri bers line, and back to ring of plug 213, the normal contacts of hey 221,the outer "lowerarmature and front contact of relay 218, the inner'lower armature and back contact of :relay 21 0, conductor 135 to ground. The current flow-ing t'hrough this ringing-Circuit is insufficient to :cause the energi zation of-re'lay 219nntil the subscriber at station 201 responds. At this time relay 219 attracts its armature and releases relay 218. The cirupper armature of relay 205 (o-battery 'and cuit for relay 219, however, is immediately opened when the automatic relay 218 becomes deenergized so that relay 219 becomes deenergized. 5 Prior to the response of the subscriber at station 201, a circuit could be traced from battery conductor 217 through supervisory lamp 222, the back contact and armature of calling supervisory relay 212 to ground. When tripping relay 219 operates and restores the automatic ringing relay 218 to normal, then talking battery is substituted for ringing current to the called subscribers line and supervisory relay 212 in series therewith becomes operated. This opens the circuit of lamp 222 which indicates that the called subscriber has answered.

We will now assume that the calling subscriber at 200 finds some difficulty and wishes to recall the operator. He will therefore depress his receiver hook once and then restore it. In other words, he will momentarily open the connection, thereby momentarily restor ing answering supervisory relay 206 to normal.

When relay 206 becomes deenergized, a circuit may be traced from battery, the lower armature and front contacts of relay 204 or from battery, the lower inner armature and front contacts of relay 205 through theback contact and right hand armature of relay 206, resistance 223, answering supervisory lamp 22 1 to ground through. the contacts of the inner upper armature of relay 20 1. The connection may also be traced from battery over the right hand armature of relay 206 through the normal contacts of the left hand armature of relay 225, winding of relay 225, the normal contacts of key 226, the alternate contacts of the inner left hand armature of relay 208 to ground. Relay 225 operates and locks through its left hand armature to battery. Lamp 224 therefore glows to show a disconnect but since the period. of deenergization of relay 206 is very short, the operator will not recognize such a flash as a disconnect signal.

As soon as relay 206 reoperates, a circuit is established from battery through the front contact and right hand armature of relay 225, the winding of relay 227, the normal contacts of the left hand armature of relay 227, the front contact and left hand armature of relay 206 to ground. Relay 227 operates and locks to ground over its left hand armature.

A battery connection is now established from the left hand armature and front contacts of relay 225 through resistances 228 and of relay 206, front contact and inner right 223, right hand armature and front contact This path'iso-f 10W enough resistanceto shunt lamp 224 and i't-"therefore becomes dark. However, relay 139 is operated and by closa contact from interrupter 140 to the w of relay 138 it causes the energi-zation of relay 137'When the interrupter 140 rotates tot-he proper position. At this time may l remains energized through its two windings in series but the conductor 137' is opened 'so as to allow lain-p 22%1tobecome i linminated. hen interrupter 1 10 moves further tlrere lay 1-38 "beoomes'deenergized and the original condition for the energization of relay 139 is reestablished. Through the operation of this flashing 'reca l l circuit, lamp go alternately lights and becomes dark. When the flashing-of lamp 224 is started by the energization of relay 227,"a circuit is established from ground at the'a-lternate-contacts of the inner left hand armature of relay 208, Windingof relay 230, outer right hand armature and front contact of relay 227, icond-u ctor 116 to inner right handxarmat'ure of relay 11%); If the operator is busy 'at this time, relay 11 9 will be operated and rel ay2 30 "90. I

pannot become energized and therefore nothmg happens in the cord-circuit except the flashing oflamp 224. As soon as the operat'o-r s'set is released as hereinbefore described, the-n battery will be placed on conductor 11 6 and this will cause the energi-zation of relay Thereilpon a groi'ind will be extended fromthe inner left hand armature and front contact-of relay 230,'wind-ing ofrelay2'07 and y thence to battery overth'e contacts of the lower armature of relay 2'04, Relay "207 becoming operated "immediately connects the operato r s set to the cord circuit so that the subscriber at station 200 may appraiseher-of the di fiiculty which he has encountered. Relay 230 in operating cha nges'the connection to its outer left hand armature from the low rate interrupter reached over conductor 137 to the high rate interrupter reached over conductor 136 so that when the operators set is thus coni nected to a cord circuit on a recall she will be given a distinctive signal to let her know to which cordcircuit she is connected.

Should the subscriber at station 200 wisha new number or wish to recall the subscriber at station 201, the operator will take plug 213' from jack 214, whereupon the front sleeve relay 205 willbecome deenergized. This removes the battery for holding relay 208 and this reiz0 lay becomes deenergized. At the same time relay 208 in coming back to normal places a ground on the one winding of relay 207 so that this will remain energized even though relay 230 becomes deenergized. Upon the re turn to normal of relay208, relays 225, 227, 230, 216 and 218 return to normal so that the circuit is now in the same condition as it would be when the operator first inserts plug 202 in jack 203. Thereafter, the operator may establish a new connection in the same manner as hereinbefore described.

What is claimed is:

1. In a telephone system, a link circuit, an operators telephone set commonly associated with said link circuit, means associated with said link circuit responsive to a temporary interruption of a connection established by said link circuit for operatively connecting said operators set to said link circuit and means individual to said operators set responsive to the busy connection thereof to delay the said operative connection of said operators set to said link circuit.

2. In a telephone system, a plurality of link circuits, an operators telephone set common tosaid link circuits, means associated with said link circuits responsive to a temporary interruption of a connection established by one of said link circuits for operatively connecting said operators set to said one of said link circuits and means individual to said operators set responsive to the busy condition thereof to delay the said operative connection of said operators set to said one of said link circuits.

3. In a telephone system, a plurality of link circuits, an; operators telephone set com monto said link circuits, means associated with said linkcircuits responsive to a temporary interrupt on of a connectlon estabilishedby one of said link circuits for operatively connecting said operators set to said one of said link circuits and means individual to said one of said link circuits responsive to said means for connecting sald operators set .to said one of said link circuits for displaying a distinctive signal indicative of said connection. I

In witness whereof, We hereunto subscribe our names, this 22 day of January 1931.

CHARLES G. SPENCER. JOHN A. HALL. 

